Hybrid-order topological insulators in a phononic crystal

Abstract

Topological phases, including the conventional first-order and higher-order topological insulators and semimetals, have emerged as a thriving topic in the fields of condensed-matter physics and material science. Usually, a topological insulator is characterized by a fixed order topological invariant and exhibits associated bulk-boundary correspondence. Here, we realize a new type of topological insulator in a bilayer phononic crystal, which hosts simultaneously the first-order and second-order topologies, referred here as the hybrid-order topological insulator. The one-dimensional gapless helical edge states, and zero-dimensional corner states coexist in the same system. The new hybrid-order topological phase may produce novel applications in topological acoustic devices.

arXiv comment4 figures

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Cited by in corpus (27)

• Topological acoustics
• Kekule Lattice in Graphdiyne: Coexistence of Phononic and Electronic Higher-Order Band Topology
• Higher-order topological phases in crystalline and non-crystalline systems: a review
• Edge State, Band Topology, and Time Boundary Effect in the Fine-Grained Categorization of Chern Insulators
• Anti-chiral edge states and hinge states based on the Haldane model
• Observation of Large-Number Corner Modes in $\mathbb{Z}$-class Higher-Order Topolectrical Circuits
• Sliding Ferroelectrics Induced Hybrid-Order Topological Phase Transitions
• Engineering exotic second-order topological semimetals by periodic driving
• Unified characterization for higher-order topological phase transitions
• Higher-order Klein bottle topological insulator in three-dimensional acoustic crystals
• Hybrid-order topological odd-parity superconductors via Floquet engineering
• Dynamical Detection of Topological Spectral Density
• Rotoinversion-symmetric bulk-hinge correspondence and its applications to higher-order Weyl semimetals
• Experimental observation of edge-dependent quantum pseudospin Hall effect
• Topological Insulators with Hybrid-order Boundary States
• Disorder-Induced Phase Transitions in Three-Dimensional Chiral Second-Order Topological Insulator
• Higher-order topology in twisted multilayer systems: a review
• Mixed higher-order topology and nodal and nodeless flat band topological phases in a superconducting multiorbital model
• Unconventional hybrid-order topological insulators
• Coexisting Euler and Stiefel-Whitney Topological Phases in Elastic Metamaterials
• Nonlinear control of photonic higher-order topological bound states in the continuum
• Hybrid-Order Topological Phase And Transition in 1H Transition Metal Compounds
• Tunable symmetry-protected higher-order topological states with fermionic atoms in bilayer optical lattices
• Topological semimetal with coexisting nodal points and nodal lines
• Breakdown of boundary criticality and exotic topological semimetals in $\mathcal{P}\mathcal{T}$-invariant systems
• Engineering Two-Dimensional Hybrid-Order Topological Insulators via Trilayer Coupling
• Realization of second-order photonic square-root topological insulators